The Effect of Functional Training on the Incidence of Shoulder Pain and Strength in Intercollegiate Swimmers Kathleen A. Swanik, C. Buz Swanik, Scott M. Lephart, and Kellie Huxel Objective: To determine whether functional training reduces the incidence of shoulder pain and increases strength in intercollegiate swimmers. Design: Pretest-posttest. Setting: Laboratory and weight room. Participants: 26 intercollegiate swimmers (13 men, 13 women). Intervention: 6-wk functional training program. Main Outcome Measures: Incidence of shoulder pain was recorded throughout the study. Isokinetic shoulder strength was assessed before and after training. Results: A t test showed significant differences (P < .05) for the incidence of shoulder pain between the experimental (mean episodes = 1.8 ± 2.1) and control (mean episodes = 4.6 ± 4.7) groups. ANOVA with repeated measures revealed no significant strength differences between groups but exhibited significant within-group increases. Conclusions: Incorporating functional exercises might reduce incidence of shoulder pain in swimmers. The results also validate the need to modify preventive programs as the demands of the sport change throughout the season. Key Words: functional rehabilitation, shoulder exercises, injury prevention Swanik KA, Swanik CB, Lephart SM, Huxel K. The effect of functional training on the incidence of shoulder pain and strength in intercollegiate swimmers. I Sport Rehabil. 2002;11:140-154. ©2002 Human Kinetics Publishers, Inc.
"Swimmer's shoulder" is the most common orthopedic pathology in compefifive swimmers, resulting in pain that interrupts training and performance.'* Popularity in swimming at recent Olympic games has encouraged technical advances, improvements in condifioning, and the use of sophisficated training equipment, but increases in the level of compefifion and training have been linked to a concurrent rise in shoulder injuries.* Kennedy and Hawkins'firstdescribed the condifion of swimmer's shoulder, not as a diagnosis but, instead, as a coUecfion of symptoms that are consistent among compefifive swimmers^' and resemble those of rotatorcuff tendinifis, subacromial bursifis, impingement syndrome, and instabilj^y 2^8-10 Several variables that could trigger the symptoms include shoulder flexibility, fafigue, improper technique, and strength i Swaruk and Swanik are with the Dept of Kinesiology, Temple University, Philadelphia, PA 19122. Lephart is with the Neuromuscular Research Laboratory, University of Pittsburgh Medical Center Center for Sports Medicine, Pittsburgh, PA 15203. Huxel is a doctoral candidate at Temple University. 140
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The treatment model for this pathology includes a decrease in yardage, anfi-inflammatory medicafion, and modality treatments before and after pracfice.''*'*''^ In most rehabilitafive environments, this treatment protocol, with the addifion of rotator-cuff strengthening, continues to be implemented and has been successful for relieving the symptoms of swimmer's shoul(jgj. 6,8,9 ^ limited amount of research, however, has invesfigated potenfial strategies for prevenfing the onset of this pathology. Funcfional training is a component of most rehabilitafion protocols that incorporates strength, endurance, agility, propriocepfion, and neuromuscular control—requirements that attempt to mimic the demands of a specific sport.'^'" Integrating functional exercises into a prevenfive training program could improve neuromuscular control and force-couple coacfivafion, as well as decrease the incidence of shoulder pathology, parficularly in overhead sports such as swimming. To date, there is mirumal inioTmation regarding specificity of functional training in relation to the incidence and prevention of shoulder pain. The purpose of this study was to determine whether funcfional training reduces the incidence of shoulder pain and increases shoulder strength in collegiate middle-distance and sprint swimmers.
Methods Subjects Twenty-six intercollegiate swimmers (13 men: height = 182.68 ± 6.10 cm, mass = 78.57 ± 8.16 kg; 13 women: height = 168.81 ± 13.13 cm, mass = 64.83 ± 8.26 kg) were randomly assigned to either a control or an experimental group. Subjects were included in this study if they had no limitations in swim and dry-land training as a result of shoulder pain and were excluded if classified as distance swimmers by their head coach or had had any previous surgeries to either shoulder. All subjects signed an informed consent approved by the university's insfitufional review board and completed a health-history questiormaire before parficipafion. Testing Procedures A concentric shoulder-strength evaluafion using the Biodex II Isokinefic Djmamometer (Shirley, NY) was administered on each subject's dominant extremity before and after a 6-week training period. All testing was completed during preseason training for the swimmers. The preseason training was required for all the athletes and included swim pracfice 6 d/wk and dry-land training 3 fimes/wk. The dry-land training involved upper and lower body weight training, lower extremity plyometrics, and cardiovascular condifioning and was supervised by the varsity coach and strength coach throughout the 6-week period.
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Before testing, a warm-up of 5 submaximal repefifions was completed, followed by a 30-second rest period. Each maximal test consisted of 10 repefifions with a 90-second rest between tests. Isokinefic testing included intemal and extemal rotafion, scapular protracfion and retracfion, and a diagonal pattem. Internal and extemal rotafion were performed in the seated position with the subject's arm in 90° of shoulder abducfion and 90° of elbowfiexion.Scapular protracfion (serratus punch) and retracfion were also performed in the seated posifion. The subject was instructed to protract and retract the scapula while maintaining full extension at the elbow. The diagonal pattem included reciprocal horizontal abducfion/ flexion and horizontal adducfion/ extension. The subject was instmcted to perform the diagonal mofion from a standing posifion while maintairung full elbow extension. All isokinefic tests were performed at speeds of 180° and 300° / s.'^ Incidence of Injury During the 6-week training period of the study, a cerfified athlefic trainer recorded incidence of injury for the experimental and control groups. The incidence of injury was defined as pain that interfered with varsity pracfice and presented as a dull aching pain at night, pain while swimming, or a feeling of the shoulder being "fired." These subjects demonstrated a posifive Neer's or Hawkin's test and required pain-management treatment and alterafions in both dry-land and swim training. The athletes who presented with shoulder pain continued parficipating in all the lower extremity training and were instmcted to kick with their arms at their side while in the pool. The funcfional program was resumed as soon as the athlete was pain free above 90° of shoulder abducfion. Functional Training Program For the subjects randomly assigned to the experimental group, the funcfional training program was performed 3 days a week for 6 consecufive weeks and was supervised by a certified athlefic trainer. The ftinctional training program comprised 7 exercises; all were specifically designed for preseason swimming and were grouped as follows. Elastic-Tubing Exercises. The first 4 exercises were perfonned for 3 sets of 10 repefifions with the subject in the standing posifion. Resistance for these exercises was provided by elasfic tubing, beginning with the second level and progressing to subsequent levels when the subject was able to complete 3 sets of 10 repefifions with ease. • Internal and external rotation: Intemal and extemal rotafion were executed in a funcfional posifion of 90° of shoulder abducfion and 90° of elbowflexion(Figures 1 and 2). Each rotafional direcfion was performed as a separate exercise to ensure equal concentric and eccentric resistance in both direcfions.
shoulder Pain and Strength in Swimmers 143
Figure 1
Internal-rotation exercise with elastic tubing.
Figure 2
External-rotation exercise with elastic tubing.
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• Horizontal abduction/flexion and horizontal adduction/extension: Diagonal
pattems of shoulder horizontal abducfion/flexion (Figure 3) and horizontal adducfion/extension (Figure 4) similar to the propriocepfive neuromuscular facilitafion D2fiexionand extension pattems were done by the subjects.^* The abduction/flexion exercise began with the subject's shoulder in horizontal adducfion and extension. The subject was instructed to flex and horizontally abduct the shoulder 180° and 140°, respecfively. The horizontal adducfion/extension exercise began with the shoulder at 180° of abducfion and 140° of flexion, and the subject was instructed to horizontally adduct and extend his or her shoulder. Prone Exercises. The prone-lying exercises were also performed in 3 sets of 10 repefifions. Free weights were used for resistance, beginning at 2 lb and increasing when the exercises could be performed without difficulty. The fifth and sixth exercises were performed with the subject lying prone on a bench. The shoulder was posifioned in 120° of abducfion/extemal rotafion for the fifth exerdse. The subject was instructed toflexhis or her shoulder while maintaining the abducted, externally rotated posifion (Figure 5).
Figure 3 tion.
Horizontal abduction/flexion exercise with elastic tubing, starting posi-
Shoulder Pain and Strength in Swimmers 145
Figure 4 tion.
Horizontal adduction/extension exercise with elastic tubing, starting posi-
Figure 5
Prone exercise, external rotation with 120° abduction.
146 Swanik etal
Figure 6 Prone exercise, external rotation with 90° abduction.
The sixth exerdse was perfonned in the same manner but with the subject's shoulder in 90° of abducfion (Figure 6). Push-Up Plus. The push-up-plus exercise was performed in 3 sets, but each set was executed unfil fafigue. The subject was instructed to perform a tradifional push-up with the hands placed shoulder-width apart. The "plus" component of the exercise required that the subject acfively protract the scapula at the top of the push-up (after full elbow extension).
Statistical Analysis Stafisfical analyses were performed using SPSS (SPSS Inc, Chicago, 111). Data are reported as mean and standard errors (± SEM). A 2-tailed t test was used to compare the incidence-of-injury measures between the experimental and control groups. Two-way (Group x Time) analyses of variance (ANOVAs) with repeated measures were performed to determine strength differences between the experimental and control groups after 6 weeks of swim and dry-land training at 180° and 300°/s during intemal and external rotafion, scapular protracfion and retracfion, and diagonal pattems. For all analyses, the level of significance was set at .05.
Results Significant differences were revealed for the incidence of shoulder pain between the experimental and control groups (f^^ = 6.87; P = .02, 2-tailed). The trained group had significantly less incidence of injury, averaging 1.8 (± 2.1) incidents, in comparison with the tintrained group, which averaged
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4.6 (± 4.7) incidents of shoulder pain over the course of the 6-week training session (Figure 7). There were no significant strength differences (P < .05) idenfified between the groups for peak-torque to body-weight rafios at either 180° or 300°/s (Table 1 and Table 2). The results revealed significant within-group increases, however, in strength at 180°/s for intemal rotafion (fj24= 17.47, P = .00), horizontal abducfion/flexion (^124= 21.31, P = .00), horizontal
Incidence of Shoulder Pain
J3 OT (D
E Group
3
4
5
6
8
10
H
Experimental
I
I Control
12
Incidence of Shoulder Pain Figure 7
Table 1
Incidence of injury.
Peak Torque to Body Weight (180 7s) Experimental Group
Direction
Pretest
Posttest
Control Group Pretest
Posttest
Internal rotation*
14.34 ± 8.43
19.20 + 8.30
16.01 ± 4.41
18.95 ± 7.30
External rotation
12.64 ± 4.34
13.99 + 4.80
13.85 ±4.06
14.53 ±4.43
Horizontal abduction/flexion*
24.95 ± 9.50
30.77 ±12.35
25.31 ± 6.90 29.52 ±9.17
Horizontal adduction/extension*
30.07 ± 13.74
34.62 ±11.30
33.85 ± 8.27 36.04 ± 8.72
9.18 ±4.69
11.54 ±4.32
Serratus punch*
*P > .05, significant difference.
9.80 ±4.10
11.55 ±4.10
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Table 2
Peak Torque to Body Weigbt (3007s) Experimental Group
Direction
Pretest
Posttest
Control Group Pretest
Posttest
Internal rotation* 15.22 ± 8.78
17.47 ±6.02
16.06 ±4.76
19.36 ±6.02
External rotation
12.60 ±3.95
13.04 ±3.93
12.92 ± 3.80
12.09 ± 3.97
Horizontal abduction/flexion 25.46 ±11.55 31.79 ± 10.93 30.64 ± 9.28
29.99 ± 13.80
Horizontal adduction/extension* 32.85 ± 15.39 40.91 ± 14.47 43.22 ± 13.76 44.87 ±11.71 Serratus punch
9.01 ± 4.34
9.57 ± 3.01
9.12 ± 3.29
9.38 ± 3.24
*P > .05, significant difference.
adducfion/extension (Fj^^ = 7.45, P = .01), and the serratus pimch (fi24~ 23.26, P = .00) for both the experimental and the control groups. No significant within-group differences were found at 180°/s for extemal rotafion (F,,^=4.23,P = .O5). Stafisfically significant within-group differences were also revealed at 300°/s. Significant overall improvement in strength was demonstrated for intemal rotafion (F^ ^^ = 7.06, P = .01) and the diagonal pattem of horizontal adducfion/extension (F^ ^^ = 5.19, P = .03). No significant within-group differences were revealed for the diagonal pattem of horizontal abduction/ flexion (Fj ^^ = 2.14, P = .16), serratus punch (Fj ^^ = 1.02, P = .32), or extemal rotation at 300° / s (Fj ^^ = 0.16, P = .70).
Discussion Forty percent to 80% of compefifive swimmers have complaints of shoulder pain that interfere with training or competifion, making it the most common orthopedic problem experienced by compefifive swimmers.^'* The subjects in our study were all swimmers with a minimum of 6 years of compefifive experience and were currently Division I varsity athletes. In order to examine a homogeneous populafion, middle-distance and sprint swimmers were included in this study because their dry-land- and swimtrairiing requirements were the same. The subjects that presented with shoulder pain complained of a dull aching pain at night, sharp pain at either the begirming or the end of swim pracfice, pain when using swim paddles, or a feeling of the shoulder being "tired," symptoms that have been consistently defined in the literature as swimmer's shoulder.^"'^'''^^ The findings in the present study revealed that the swimmers who completed
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the funcfional training program experienced significantly fewer incidents of interfering shoulder pain than did the control group. The funcfional exercises used in this study did not result in significant strength increases between the groups. The reducfion of interfering shoulder pain could be the result, however, of acquiring neuromuscular adaptafions resulting in improved muscle efficiency. Swimmer's shoulder has been linked to range of mofion, improper technique, muscle fafigue, and strength imbalances. Swimmers typically present with an increase in extemal rotafion and subsequent decrease in intemal rotafion when compared with normafive data.^-^-^' This change in mofion is thought to alter glenohumeral kinematics, predisposing the athlete to swimmer's shoulder and anterior instability.^"-^' Greipp* was able to predict swimmer's shoulder with 93% accuracy by assessing shoulder flexibility and found a significant correlafion between anterior shoulder inflexibility and shoulder pain. Several other research studies, however, have not been able to idenfify a correlafion between flexibility and shoulder Muscle fafigue has also been linked to the onset of swimmer's shoulder as a result of improper technique or a disrupfion in glenohumeral and scapulothoracic mofions.* Improper technique causes impingement symptoms by compromising vascularity, parficularly at the entry phase of the stroke.*' Although uncommon in those performing at high levels of compefifion, a common technical mistake made by swimmers is "dropping the elbows" during the recovery phase of the stroke. This results in an increase in extemal rotafion, placing unnecessary stress on the stafic stabilizers (ligaments and capsule) while fafiguing the dynamic stabilizers (rotator cuff, biceps, and scapular musculature) of the glenohumeral joint.^ Fafigue of the rotator cuff appears to decrease neuromuscular control, allowing for superior humeral-head migrafion and increasing the stress on both stafic and dynamic shoulder stabilizers. Saffran" documented the fact that with fafigue, a muscle's capacity to absorb energy is reduced, thus compromising dynamic joint stability. In swinuning, this might alter scapulothoracic and glenohumeral mechanics, further predisposing the athlete to injury."" Therefore, as the season progresses, exercises with an emphasis on endurance should be slowly introduced into the funcfional training program. Glenohumeral- and scapulothoracic-strength developments and deficits have also been identified as contributing to swimmer's shoulder. Several studies have compared agonist:antagonist strength rafios for shoulder adduction/abduction and intemal and extemal rotafion in both upper extremity athletes and nonathletes. Although absolute strength was greater in athletes, the rafios were the same for both groups (2:1 for adducfion/ abducfion and 3:2 for internal/external rotafion).'"-^"^ This study invesfigated exercises that replicated sport-specific posifions and pattems and measured strength for intemal and extemal rotafion (at 90° of abducfion and elbow flexion) and diagonal patterns of flexion/abduction and
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extension/ adducfion. The diagonal pattems attempted to assess the "funcfional" strength of the glenohumeral and scapulothoracic musculature together and therefore were measured in mulfiplanar mofions rather than true cardinal planes. The diagonal-pattern strength assessments did reveal increases in strength over fime, which were attributed to the demands of swim training. Further investigafion needs to be done, however, on the outcome of incorporating exercises in these funcfional positions throughout the course of a compefifive season. A 3:2 strength rafio has been established between intemal and extemal rotafion for upper extremity athletes and nonathletes.^*"'^'^*-^'^' Shoulderstrength "imbalance" is thought to occur naturally as a result of a greater cross-secfional diameter of the intemal rotator muscles, resulting in higher force output when compared with the extemal rotators.^-^' In addifion, shoulder-torque rafio adaptafions have been found to occur in athletes in upper extremity sports such as swimming, baseball, and water polo, indicating that the shoulder internal rotators and adductors are "superdeveloped" in comparison with the external rotators and abductors. These changes have been attributed to the repefifive demands placed on the shoulder over the course of a season and compefifive swimming career that predispose the shoulder to muscle dysfunction."'^^"^ There are limited data on shoulder-strength adaptafions over time, making comparisons with previous studies difficult. To our knowledge, this is the first study to prospecfively examine shoulder strength over 6 weeks of swim and dry-land training. Pretest intemal to extemal shoulder-strength rafios were 1:1, indicating that the strength was balanced between the 2 muscle groups at 180° and 300°/s. After 6 weeks of training there was a significant increase in internal-rotation strength for both groups, at both speeds, without significant increases in external-rotation strength. The significant finding in intemal-rotafion strength resulted in the strength rafio moving closer to 3:2, supporting previous research.^" The lack of significant strength differences identified between groups could be the result of several factors. Typically, larger increases in strength are observed at the beginning of a training cycle than during the middle or at the end of a compefifive season. Because this study took place during the preseason, both groups were involved in condifioning programs that required high resistance, eliciting strength gains that might have accounted for the lack of significant group differences. Therefore, the amount of weight or level of resistance used during the ftmcfional exercises was not enough to induce significant strength adaptafions between groups. We believe that these exercises instead placed the shoulder in functional positions, with a resistance that facilitated more efficient muscle-firing sequences. Functional training might encourage force couples to work in concert and therefore improve joint protecfion. Synchronizing the force-couple acfivity will improve dynamic stability, minimize chronic microtrauma caused by unnecessary humeral-head translafion, and, therefore, decrease the incidence of
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shoulder pain. These results validate the need to modify the elements of the funcfional training program as the demands of swim training and compefifion progress throughout the season, placing emphasis on extemal-rotafion strength and endurance of the glenohumeral and scapulothoracic musculature. For optimal athlefic performance, the dynamic stabilizers of the shoulder complex must fire in a consistent and coordinated fashion. Conditioning exercises should replicate the funcfional requirements associated with sport-specific skills."** Unfortunately, most traditional weight-training programs fail to address the dynamic strength and endurance requirements of swimming, thus promoting shoulder dysfunction. Funcfional exercises were incorporated in daily dry-land training in this study in an attempt to target specific muscle groups in posifions relative to the demands of the sport. Maximum recruitment of muscles responsible for humeral and scapular rotafion and stabilizafion is necessary to provide dynamic stability of the glenohumeral joint and scapulothoracic articulation."" Several researchers agree that exercises should be implemented in posifions of vulnerability, thus inducing neural adaptafions for dynamic restraint."'"'^^-^ Therefore, intemal- and extemal-rotafion exercises were implemented with the shoulder abducted to 90°. Combined movement pattems are believed to enhance force-couple coactivafion and neuromuscular control, improving dynamic stability of the shoulder." For this reason, elasfic-tube exercises in diagonal pattems of shoulder extension/adducfion and shoulder flexion/ abducfion were included in the ftmcfional training program. Prone scaption with extemal rotafion at 90° and 120° was performed to maximize firing of the rotator cuff and scapular stabilizers.'* The funcfional training program was inifiated at the beginning of the swimmers' strengthening phase, and for this reason all tasks were implemented using 3 sets of 10 repefifions. Because endurance and strength are integral components of promoting and maintaining long-term dynamic stabilizafion, the push-up-plus exercise was performed until fafigue. This exercise also addressed glenohumeral and scapulothoracic control. The addifion of the "plus" phase of the exerdse inifiated scapular protracfion and serratus anterior strengthening while continuing to maintain joint compression throughout the exercise.""-^^ The results of this study indicate that funcfional training reduces the incidence of injury in swimmers. Strength changes did occur over a 6-week period, further validafing the need to constantly reevaluate funcfional or dry-land training programs for strength and endurance developments and deficits, as well as to incorporate current demands of the sport throughout compefifive and off-season programs. If the study were conducted just before or during the compefifive season, we would suggest emphasizing the endurance component of the training by using higher repefifions and, possibly, lower resistance. Furthermore, decreasing or eliminating the amount of internal and adducfion types of exercises and confinuing to emphasize extemal rotation and abductor strength is recommended.
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Conclusion There was significantly less incidence of shoulder pain in the swinuners who parficipated in the funcfional training program than in the control group. Significant strength adaptafions that occurred within the groups necessitate change in weight-training programs over the course of a compefifive swim season. No significant strength differences were evident between groups. This study does support the importance, however, of incorporating funcfional strengthening exercises into swim-trair\ing regimens. These exercises performed at sport-specific angles and demands result in more efficient muscle-firing sequences, allowing for opfimal joint protecfion and, therefore, decreasing the likelihood of the occurrence of swimmer's shoulder in this populafion.
References 1. Beach ML, Whitney SL, Dickoff-Hoffman SA. Relationship of shoulder flexibility, strength, and endurance to shoulder pain in competitive swimmers. / Orthop Sports Phys Ther. 1992;16:262-268. 2. AUegrucci M, Whitney SL, Irrgang JJ. Clinical implications of secondary impingement of the shoulder in freestyle swimmers. / Orthop Sports Phys Ther. 1994;20:307-318. 3. McMaster WC. Painful shoulder in swimmers: a diagnostic challenge. Physician Sportsmed. 1986;14:108-122. 4. Dominguez RH. Shoulder pain in swimmers. Physician Sportsmed. 1980;8:35-42. 5. Richardson AB. Overuse syndromes in baseball, tennis, gymnastics, and swimming. Clin Sports Med. 1983;2:379-390. 6. Richardson AB, Jobe FW, Collins HR. The shoulder in competitive swimming. Am ] Sports Med. 1980;8:159-163. 7. Cuillo JV, Stevens GG. The prevention and treatment of injuries to the shoulder in swimmers. Sports Med. 1989;7:182-204. 8. Greipp JF. Swimmer's shoulder: the influence of flexibility and weight training. Physician Sportsmed. 1985;13:92-105. 9. Kennedy JC, Hawkins RJ. Swimmer's shoulder. Physician Sportsmed. 1974;2:3438. 10. Kermedy JC, Hawkins RJ, Krissoff WB. Orthopaedic manifestations of swimming. Am ] Sports Med. 1978;6:309-322. 11. McMaster WC, Long SC, Caiozzo VJ. Shoulder torque changes in the swimming athlete. Am ] Sports Med. 1992;20:323-327. 12. Hawkins RJ, Kennedy JC. Impingement syndrome in athletes. Am ] Sports Med. 1980;8:151-158. 13. Lephart SM, Henry TJ- The physiological basis for open and closed kinetic chain rehabilitation for the upper extremity. / Sport RehabiL 1996;5:71-87.
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14. Lephart SM, Kocher MS. The role of exerdse in the prevention of shoulder disorders. In: Matsen FA, Fu FH, Hawkins RJ, eds. The Shoulder: A Balance of Mobility and Stability. Rosemont, 111: American Academy of Orthopaedic Surgeons; 1993:597-620. 15. Biodex Corporation. Operations/Application ManuaL 2nd ed. Shirley, NY: Biodex Corp; 1987. 16. Amheim DA, Prentice WE. Principles ofAthletic Training. 9th ed. Madison, Wise: Brown & Benchmark; 1997. 17. Bak K, Fauno P. Clinical finding Ln competitive swimmers with shoulder pain. Am ] Sports Med. 1997;25:254-260. 18. Neer CS II. Anterior acromioplasty for the chronic impingement syndrome in the shoulder: a preliminary report. / Bone ]oint Surg Am. 1972;54:41-50. 19. Bigliani LU, Codd TP, Connor PM, Levine WN, Littlefield MA, Hershon SJ. Shoulder motion and laxity in the professional baseball player. Am ] Sports Med. 1997;25:609-613. 20. Borsa PA, Lephart SM, Kocher MS, Lephart SP. Functional assessment and rehabilitation of shoulder proprioception for glenohumeral instability. / Sport RehabiL 1994;3:84-104. 21. Wilk KE, Arrigo C. Current concepts in the rehabilitation of the athletic shoulder. / Orthop Sports Phys Ther 1993;18:365-375. 22. Jobe FW, Kvitne RS. Shoulder pain in the overhand or throwing athlete: the relationship of anterior instability and rotator cuff impingement. Orthop Rev. 1989;18:963-975. 23. Safran MR, Garrett WE, Seaber AV, Glisson RR, Ribbeck BM. The role of warmup in muscular injury prevention. Am ] Sports Med. 1988;16:123-129. 24. Connelly Maddux RE, Kibler WB, Uhl T. Isokinetic peak torque and work values for the shoulder. / Orthop Sports Phys Ther 1989;10:264-269. 25. Cook EE, Gray VL, Savinar-Norgue E, Medeiros J. Shoulder antagonistic strength ratios: a comparison between college-level baseball pitchers and nonpitchers. / Orthop Sports Phys Ther 1987;8:451-461. 26. Ivey FM, Calhoun JH, Rusche K, Bierschenk J. Isokinetic testing of shoulder strength: normal values. Arch Phys Med RehabiL 1985;66:384-386. 27. Weldon G, Snouse SL, Shultz S. Normative strength values for knee, shoulder, elbow and ankle for females ages 9-73 as determined by isokinetic testing. / Athletic Train. 1988;23:325-331. 28. Murray MP, Gore DR, Gardner GM, Mollinger LA. Shoulder motion and muscle strength of normal men and women in two age groups. Clin Orthop. 1985;192:268-273. 29. Brown LP, Neihues SA, Harrah A, Yavorsky P, Hirshman HR Upper extremity range of motion and isokinetic strength of the intemal and extemal shoulder rotators in Major League Baseball players. Am ] Sports Med. 1988;16:577-585. 30. Iannotti J. Lesions of the rotator cuff. In: Matsen FA, Fu FH, Hawkins RJ, eds. The Shoulder: A Balance of Mobility and Stability. Rosemont, HI: American Acad-
emy of Orthopaedic Surgeons; 1993:239-252.
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31. Shklar A, Dvir Z. Isokinetic strength relationships in shoulder muscles. Clin Biomech. 1995;10(7):369-373. 32. Aldemick GJ, Kuck DJ. Isokinetic shoulder strength of high school and college-aged pitchers. / Orthop Sports Phys Ther 1986;7:163-172. 33. Hinton RY. Isokinetic evaluation of shoulder rotational strength in high school baseball pitchers. Am ] Sports Med. 1988;16:274-279. 34. McMaster WC, Long SC, Caiozzo VJ. Isokinetic torque imbalances in the rotator cuff of the elite water polo player. Am ] Sports Med. 1991;19:72-75. 35. Davies GJ, Dickoff-Hoffman S. Neuromuscular testing and rehabilitation of the shoulder complex. / Orthop Sports Phys Ther. 1993;18:449-458. 36. Townsend H, Jobe FW, Pink M, Perry J. Electromyographic analysis of the glenohumeral muscles during a baseball rehabilitation program. Am ] Sports Med. 1991;19:264-272. 37. Moseley JB, Jobe FW, Pink M, Perry J, Tibone J. EMG analysis of the scapular muscles during a shoulder rehabilitation program. Am ] Sports Med. 1992;20:128134.
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